| Abstract
| - Clusters of styrene with several atoms and smallmolecules were prepared and studied in a supersonic jet bylaser-induced fluorescence (LIF) from S1 andresonance-enhanced multiphoton ionization (REMPI) usingS1as the resonant intermediate state. The dissociation limit can bedetermined in many cases (e.g., for argon,CO2, and ammonia) by recording the excess energy at whichfluorescence from the cluster disappears andstyrene fluorescence appears. Parent ion signals are easilyobservable from clusters excited to energiesexceeding the dissociation threshold in S1, as determinedby LIF. This indicates a relatively long lifetime ofthe electronically excited cluster on the ionization time scale.The styrene−trimethylamine system, which isreactive in liquid solution, exhibits a very different fluorescencebehavior than all others. Two 1:1 styrene−trimethylamine clusters are observed by fluorescence excitation.One of them exhibits locally excited emissionupon absorption near the origin, but at higher excitation energies, theemission is exciplex-type. The othershows exciplex emission at all excitation energies, including the 0−0band. The data indicate at least twononradiative processes competing with exciplex formation and with itsradiative decay. The relation to solutionphase photochemistry is discussed.
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